template-meta-programming

I'm told that the template system in C++ is Turing-complete at compile time. This is mentioned in this post and also on wikipedia . Can you provide a nontrivial example of a computation that exploits this property? Is this fact useful in practice? Example #include <iostream> template <int N> struct Factorial { enum { val = Factorial<N-1>::val * N }; }; template<> struct Factorial<0> { enum { val = 1 }; }; int main() { // Note this value is generated at compile time. // Also note that most compilers have a limit on the depth of the recursion available. std::cout << Factorial<4>::val << "\n"; }

I want to represent the description of a persistent memory layout (e.g. Flash or EEPROM device) statically embedded in the program code (preferably in the ROM section), from a set of variadic template parameters, where the necessary offsets are automatically calculated at compile time. The goal is to create an appropriate array initializer, that can be iterated at runtime, without the restrictions you'll get with std::get(std::tuple) , which requires compile time indexing. 1st approach I have created a simple data item descriptor class that binds a particular ID (should be provided as an enum

In this answer I define a template based on the type's is_arithmetic property: template<typename T> enable_if_t<is_arithmetic<T>::value, string> stringify(T t){ return to_string(t); } template<typename T> enable_if_t<!is_arithmetic<T>::value, string> stringify(T t){ return static_cast<ostringstream&>(ostringstream() << t).str(); } dyp suggests that rather than the is_arithmetic property of the type, that whether to_string is defined for the type be the template selection criteria. This is clearly desirable, but I don't know a way to say: If std::to_string is not defined then use the